This invention relates generally to endotracheal tubes which are inserted through the mouths of patients to facilitate artificial ventilation. More particularly, the present invention relates to endotracheal tubes which employ inflatable structures to provide an air-tight seal between the tube and the surrounding tracheal wall.
Endotracheal tubes which are inserted through the mouth or nasal passages of a patient for extension into the trachea have been widely used in the medical arts for a number of years. Such endotracheal tubes conventionally employ an external inflatable sleeve or cuff. The tube is insertable into the trachea. The cuff is then inflated with air or other fluids to produce an air-tight seal between the tube and the surrounding body tissue. The cuff is conventionally located at various positions along the inner wall of the pharynx, larynx or trachea according to the specific endotracheal tube design. A wide variety of various forms of endotracheal tubes have been employed.
While conventional endotracheal tubes have been advantageously employed to provide numerous beneficial medical achievements, one of the most prominent problems associated with endotracheal tubes in general is the tissue damage which is caused due to contact between the endotracheal tube, and in particular, the distal end portions of the tube, and the very delicate tissues which line the trachea and the larynx. During periods of prolonged intubation, contact and pressure from the tube may have a pronounced effect on surrounding tissue, and in some instances, result in the formation of scar tissue. A number of devices have been proposed for reducing the contact between the endotracheal tube and the surrounding tissue during prolonged intubation. Devices such as shown Gebauer U.S. Pat. No. 2,175,726, Winder U.S. Pat. No. 2,210,744, Elam U.S. Pat. No. 4,091,816 and Eliachar U.S. Pat. No. 4,700,700 have employed plural cuff arrangements to minimize contact between the tube and the tissue.
Eliachar U.S. Pat. No. 4,700,700 discloses an endotracheal tube which employs an upper inflatable-deflatable cuff which is fixed in position above the larynx. The upper cuff surrounds a predetermined portion of the posterior round surface of the tube. A lower inflatable-deflatable cuff, which is spaced from the upper cuff, is positioned at a pre-determined distance below the larynx. The upper cuff is operative when inflated to engage a posterior portion of the pharynx to effect an alignment of the tube relative to the larynx wherein the axis of the tube portion within the larynx is maintained central thereto away from the posterior portion of the larynx and the lower cuff is operative upon inflation to sealingly engage the inner wall of the trachea. The cuffs are separately inflatable and deflatable. Channels in the wall of the tube extend from the cuffs to an upper portion of the tube for inflating and deflating the cuffs.
Elam U.S. Pat. No. 4,091,816 discloses an endotracheal tube which employs two inflatable cuffs. The balloons are shaped and positioned to fully occupy the spaces above and below the open larynx. The two cuffs have a common inflation channel which freely communicates between the cuffs. Elastic properties of the upper cuff cooperate to form a pressure relief system for the lower cuff which is essentially non-elastic. A relatively short segment of uncuffed tube facilitates the obtaining of a pre-determined anatomical location of the cuffs and resultant selective positioning of the tube within the trachea. The seals of the cuffs can be maintained at a relatively low pressure.
Although the use of various double cuff arrangements have proved somewhat satisfactory, optimal use of endotracheal tubes can be enhanced with additional refinements to the spacial relationships and dimensional relationships between the cuffs or balloons, as well as additional refinements to the cuff design and the placement of the tube in the patient. Accordingly, the present invention is directed to providing an improved endotracheal tube having a double inflatable cuff arrangement.